Brush-holder and brush for dynamo-electric machines.



AEATEN-TED' JUNE 2, 1903.

E. LUNDELL. EEUSH HULUEH ANU BRUSH EOE DYNAMU ELEUTHIU MACHINES.

APPLICATION FILED NOV. 26. 1902.

No MODEL.

,l 1,- X Tummy?? rllll Patented June 2, 1903.

PATENT OFFICE.

ROBERT LUNDELL, OF NEW YORK, N. Y.

BRUSH-HOLDER AND BRUSH FOR DYNAMO-ELECTRIC MACHINES.`

SPECFIECATION forming part of Letters Patent No. 729,878, dated June 2, 1903. Bpplieationiiled November 26,1902. Serial No. 182.871. (No model.)

T0 all whom t may concern:

Be it known that I, ROBERT LUNDELL, a citizen of theA United States, residing at New York, borough of Manhattan, county and State of New York, have made a new and use ful invention in Brush-Holders and Brushes for Dynamo-Electric Machines, of which the following is a specilication.

The present invention relates to improvements in brush-holders and brushes for dynamo-electric machines, and has particular reference to the class of brushes and brushholders described by me in a prior United States Patent, No. 672,601, granted April 23, 1901.

The invention is especially applicable to dynamos and motors which are arranged to run in one direction; and its chief objects are, first, to provide a brush-holder and brushes which shall insure perfect commutation at variable field strength and which shall make it possible to adj ust the compounding of such a machine by varying the brush position, and consequently the armature reaction, without trouble from sparking second, to insure perfect contact between the commutator, the brushes, and the holder, particularly when used in connection with high-speed machines.

For a clear understanding of the invention reference is made to the accompanying drawings, in which- Figure 1 is an end view of my improved brush-holder, and Fig. 2 a side view of the same. Fig. 3 is a plan view of the tension device or mechanism employed for giving the individu al brushes their proper pressure against the commutator, as well as proper contact with the main portion of the brush-holder. Fi g. 4 is a plan view of the piece or sleeve which supports the above-mentioned tension device. Fig. 5 is an end view of the same detail. Fig. G is a side view of thetension or pressure lever, and Fig. 7 is a plan view of the same. Fig. S is a side viewof the contacteleverwhich presses the individual brush against the main portion of the bruslrholder, and Fig. 0 is an end view of the same. Figs. 10,` 11, and 12 are small details, which will be referred to hereinafter.

Referring now to the drawings in detail, and particularly to Figs. 1 and 2, it will be noticed that the right-hand corner of Fig. 1 is shown in section. Said section is taken on the line y of' Fig. 2. 1 represents the main part of the brush-holder. It consists of a composition-casting (in one piece) having a wedge-shaped central portion, with four arms or extensions at the ends to support the tension mechanism, and a stud for securing the brush-holder to a rocker-arm or brush-holder ring in the usual manner. Two-sets of carbon brushes 2 and 3, as shown in Fig. 1, are arranged to be fed against the commutator and pressed against the above mentioned wedge-shaped portion of the holder. Fig. l shows the brushes in a worn-out state and indicates also in dotted lines the original size of the brushes. One set of these brushes is preferably of considerably higher resistance than the other set, and the machine is supposed to be running in such a direction that the high-resistance brush is located at the leaving edge of the low-resistance brush. The two sets of brushesmay preferably have diferent lubricating qualities to insure best results from their combined action, and one set at least may be thinner than a commutatorbar to prevent rupture of contact, owing to some slight iiaw in the surface of the commutator. The brushes are fed forward against the commutatcr by levers G 7 dac. These levers are shown in detail by Figs. 6 and 7. Another set of levers 10, rbc., are employed for pressing the brushes firmly against the main portion of the holder. One of' the said levers is shown in Fig. 1, and Figs. 8 and 9 will serve to fully illustrate its construction.

The levers 7 and 10 (see Fig. 1) are both supported or hinged on the projecting arms of a sleeve 11. (Show-n in detail in Figs. 4 and 5.) This sleeve is in turn supported by the rod 12, which connects the two right-hand extensions of the casting 1.

It will be noticed on further inspection of Fig. 1 that the pressuredever 7 and the contact-lever 10 are both actuated by the same spring mechanism. This is an important feature of the brush-holder, as it prevents the trouble which would result from two independent adjustments or from the use of two springs, one of which may accidentally be applied with too great a force as compared with the other.

By means of the present invention the brush is firmly held in au adjustable or elastic IDO pocket formed by the main portion of the brush-holder on onezside and the contactlever 10 on the other side of the brush. This arrangement insures excellent contact between the brush and theholder and prevents the brush from rocking and wearing on its edges. The distance: between the pivot or pin on which the lever 10 is hinged and the hole in the lever from which one end of the tension-spring 13 is attached bears such a relation t0 the corresponding distance between the pivots 14: 5nd 15 of the pressure-lever 7 and the point at which the other end of the spring is attached that the brush will always slide freely in its pocket, no matter how the tension device is adjusted. ln other words, the workin g radii of the two different levers are so proportioned that the lever 7 will always be capable of pressing the brush against the commutator, no matter how the tension device is adjusted,

The above statement is of course meant to apply to a range of movement oi' the lever 7 between the maximum and the minimum length of the brush. lf the lever 7 is thrown back more than about sixty degrees the construction is such as to permit of the spring passing over on the other side of the center of the pivots 14 and 15. (See Figs. 1, 2, and 3.) This arrangement causes the lever 7 to remain back init's extreme open positiomwhich makes it very convenient tcput in or to remove the brush.

It will be noticed that the ad justing-screw 16 passes through a small plate 17, having pivots at its sides, as clearly shown in Figs. 10 and 11. The supporting-sleeve 11, with levers 7 and 10, spring 13, adjusting-screw 1G, plate 17, and thumb-nut 1Sfor1n one coinplete set of details for one individual brush. (See particularly Fig. 3.) The important feature of the same is that the two means em ployed-iirst, for feeding the carbon against the commutator, and, second, for securing contact between the brush and the holderare both actuated or controlled by a mutual tension device. The brush-holder is, as the drawings illustrate, symmetrical on both sides of theV center line of the main part 1, the two sets of brushes having precisely the same adjusting and pressure devices. The adjustable or elastic pockets for the `brushes will easily accommodate brushes of different thickness without change in the proportions of the various parts.

Another important feature of the holder is that it permits the brushes of each set to abut against one another at their ends and the two sets of brushes at their contact'edges. This feature prevents ridges from appearing on the surface 'of the commutator and reduces the dimensions of the commutator to a minimum.

Having thus described myinvention, what I cla-iin, and desire to secure by Letters Patent of the United States, is-

1. A brush-holder having two sets of brushes of different resistance located after one another on the periphery of a commutator; in combination with means for pressing the brushes against the commutator and against the main supporting portion of the holder, said main supporting portion being located between the brushes.

2. A brush-holder having two sets of brushes located after one another on the periphery of a commutator and inclined at an angle toward each other; in combination with means for pressing the brushes against the com inutator and against the main supporting portion of the holder, said main supporting poi tion being located between the brushes.

A brush-holder consisting of a wedgeshaped central portion with brushes on opposite sides of the same; in combination with means for pressing the brushes against the commutator and against the said central portion.

ln testimony whereof l have signed my name to this vspecification in the presence of two subscribing witnesses.

ROBERT LUNDELL.

lVitness-es:

C. J. KINTNER, M. l?. KEATING. 

